Product dispensers that heat a product prior to or at the time of dispensing are known. Some heating dispensers heat more than is dispensed, which exposes product in the container to temperature cycling. However, many cosmetic and dermatologic products are unstable when subjected to temperature cycling. Temperature cycling can cause degradation or other unwanted alteration of the product. Degradation includes, for example, a breakdown in viscosity, changes in color and odor. Another unwanted alteration might be that an inactivated ingredient in a portion of product becomes activated, even though it has not been dispensed. For products that will be changed structurally or chemically by the application of too much heat or from being too often heated, these prior art devices are wholly unsuitable. Therefore, prior art devices that heat even a portion of the reservoir, or that heat more product than will be used, are unsuitable for many cosmetic applications. Another disadvantage of devices that heat the reservoir, or that heat more product than will be used, is the power consumed. Far more power must be consumed by these devices because they aim to raise the temperature of a greater mass of product than the present invention. This is costly and inconvenient if batteries need to be replaced often. Some heating dispensers are inconsistent in the amount of time that a portion of product is heated. This happens, for example, when the heating time is variably controlled by a user dispensing the product. U.S. Pat. No. 7,448,814 discloses a device having this drawback. A portion of the reservoir is flexible, and when depressed by a user an amount of heated product is dispensed. But the amount of product dispensed in variable because it depends how hard the user depresses the flexible portion. Some heating dispensers require an external device for operation, like a separate power supply or separate heating component. Some heating dispensers require 100 volts of electricity or more. The electronics of these devices may include external power cords. External power cords tend to deteriorate and be unwieldy; the plug-in power cord does not offer the mobility and safety of batteries, and the voltage used is much higher than that of batteries. Some heating dispensers are only useful for relatively viscous products, because the device would leak if the viscosity of the heated product became too low. Likewise, some heating dispensers are not useful for storing a flowable product when not in use, or they require extra componentry. Some heating dispensers are aesthetically or ergonomically unsuitable for the personal care marketplace. Many heating dispensers are not handheld, meaning that they can be held in the air and product dispensed with one hand. Many heating dispensers would require too long to heat a product compared to what is commercially acceptable in the personal care marketplace. Many heating dispensers are not in the form of a lotion pump or liquid spray pump, so familiar to the personal care and fragrance consumer.
All of this is in contrast to the present invention, wherein: the product remaining in the dispenser is not substantially heated and remains in good condition for future use; relatively little power is consumed; the amount of time that a portion of product is heated is consistent from dose to dose; no external device for operation is required; only battery power is required; there are no external power cords; the device is handheld and completely portable, usable anywhere; low viscosity fluids will not leak; the present heating dispenser is aesthetically or ergonomically suitable for the personal care marketplace, because the form and functioning of the device a completely familiar to the consumer; a dose of product can be heated in commercially acceptable amount of time.
Furthermore, it is known for heated cosmetic and personal care dispensers to utilize conventional, flexible metallic wiring and contacts for conducting electricity from a power source to a switch, then to a heating element and possibly to one or more light indicators and temperature controls, before returning to the power source. If more than one independent circuit is required, then the number of wires and electrical connections increases proportionately. In contrast, heating dispensers according to embodiments of the present invention do not use metal wire conductors or use substantially fewer, do not have the space constraints associated with using wire circuitry, substantially reduce the labor required to assemble the dispenser, have more reliable electrical connections and sophisticated electrical options, and reduced circuit length.